MULTI-STACKED SEMICONDUCTOR DEVICE INCLUDING GATE STRUCTURES WITH RMG

There is provided a multi-stack semiconductor device including: a lower field effect transistor in which a lower channel structure is surrounded by a lower gate structure, the lower gate structure including a lower gate dielectric layer, a lower work function metal layer, and a lower gate metal pattern; and an upper field effect transistor in which an upper channel structure is surrounded by an upper gate structure including an upper gate dielectric layer, an upper work function metal layer, and an upper gate metal pattern, where the channel width of the upper channel structure is smaller than the channel width of the lower channel structure, and wherein a replacement metal gate (RMG) inner spacer is formed between the lower work function metal layer and the upper work function metal layer in a region where the lower channel structure does not vertically overlap with the upper channel structure. 提供了一种多堆叠半导体器件，其包括：下场效应晶体管，在下场效应晶体管中下沟道结构由下栅极结构围绕，下栅极结构包括下栅极电介质层、下功函数金属层和下栅极金属图案；以及上场效应晶体管，在上场效应晶体管中上沟道结构由上栅极结构围绕，上栅